Apparatus for making perspective drawings



Sept. 24, 1957 F. M. MULLER 2,807,090

APPARATUS FOR MAKING PERSPECTIVE DRAWINGS Filed May 29, 1955 oLII/II/I/I/II/Il/II/l/l/V/l/II I [L] I WVENTOR F.. MAX- MULLER PATENT AGENT United States Patent Patented Sept. 24, 1957 APPARATUS FOR MARIN G PERSPECTIVE DRAWINGS Fritz Max Miiller, Zurich, Switzerland Application May 29, 1953, Serial No. 358,245 Claims priority, application switzerland May 30, 1952 3 Claims. (Cl. 33-47) g The present invention relates to an apparatus for making perspective drawings by means of ground plans and geometrical views, such as elevational and side views of the object or article to be illustrated.

An object of this invention is to provide two drawing boards, viz: a substantially horizontal drawing board adapted to receive a geometrical view of the object or article to be perspectively drawn and the perspective drawing itself and a substantially vertical drawing board to which a ground plan of said object or article is secured at a place properly selected with respect to the viewers position, whereby the latters position is selected as a fixed point above the drawing board.

It is a further object of the present invention to mount an arm or straight edge with a straight mark line throughout its length rotatably about a fixed point, i. e. a pivot pin attached to the vertical drawing board, the effective length of said arm or straight edge being adjustable. This: arm or edge is used to project the heights to the image plane.

It is another object of this invention to provide a vertically and slidably guided, horizontal straight edge on the substantially vertical drawing board, said edge having a graduation on one of its sides.

It is a still further object of the invention to provide a square, such as a T-square, with a graduation on the horizontal drawing board, one side of said board being equipped with an edge having a graduation, said edge being slidable, i. e. parallelly extensible with respect to said side of the drawing board in the plane of the latter.

These and other important objects and advantageous features of this invention, including the method steps of making perspective drawings, will be apparent from the following detailed description and drawing, appended thereto, wherein merely for the purposes of disclosure non-limitative embodiments of this invention are set forth.

Figure 1 shows a perspective view of the new apparatus in actual use for making a perspective drawing.

Figure 2 is a perspective illustration of a part of a modified vertical drawing board, as that in Figure 1, showing in detail the guiding and locking means for the horizontal straight edge slidably mounted on this board.

Figure 3 shows, on an enlarged scale, a longitudinal section through the part shown in Figure 2 along the line 33.

Figure 4 illustrates, also on an enlarged scale, a cross section through the same part along the line 44 of Figure 2.

Referring now more specifically to the embodiment of the invention illustrated in Fig. l of the accompanying drawing, a horizontally disposed drawing board 1, which may be of the conventional type, is provided. A drawing board 2 is vertically mounted thereon by means of a supporting base member 3, preferably close to the rear edge of said board 2.

While in the embodiment shown in Figure l the two drawing boards are firmly and immovably secured to one another by means of said base member .3, it is possible to provide hinge means between the drawing boards so that the vertical board 2 can be turned toward or folded down on the horizontal board 1, when the apparatus is not in use. A transparent, horizontal straight edge 5 having a long handle 6 and a graduation 7 along its lower side is slidably mounted on the vertical drawing board 2. This straight edge 5 which is parallelly guided, for example, with the aid of vertical guiding means 4 on both sides of the board 2, or by a single guiding member on one side of this board, serves to mark the selected image plane and' to read the locations of the points to be projected and of the points projected to the image plane b.

Figure 2 illustrates the guiding and locking means for the straight edge 5. A profiled rail 20, for example, of metal having the cross section of a trapezoid with an open smaller side is provided in and along at least one of the sides of the vertical drawing board 2, acting as guiding means 4 for the straight edge 5 (see Fig. 1). As shown in Figures 2, 3 and 4, a slide 18 is displaceably or slidably mounted in said profiled rail 20, whereby the adjusted position of this slide 18 can be fixed, i. e. the straight edge 5 can be locked at any desired place on its travel over the vertical drawing board 2. The slide 18 comprises two small blocks 17 in shape of trapezoids made, for example, of wood. Each of these blocks 17 has a notch 23 open at the smaller side of the trapezoid and adapted to receive a common pin 22 and individual compression springs 24 supporting said pin 22 within each of said notches 23. Four rollers 25 support the slide 18 in the rail 20, said rollers being mounted on the legs of two springy U-shaped members 30 secured to the pin 22 at their center portions. The open side of the slide 18 is covered or closed by a plate 21 to which the blocks 17 are fastened, said plate having an extension 26 for securing the straight edge 5 thereto, for example, by means of bolts or screws. The straight edge 5 can be displaced or moved over the vertical drawing board 2 upon inserting a finger in a center oval cutout of the plate 21 and manually exerting a pressure on the pin 22 overcoming the force of the springy members 30 and thereby the locking force of the wedging blocks 17 normally frictionally engaging the inner walls of the rail 20. The walls at the open side of this profiled rail 20 embedded in the material of the vertical drawing board 2 end in flanges which are flush with this board. The left flange supports a guide rod protruding from the drawing board surface and ending in a round, almost circular, portion 29 on which a slide 28 is displaceably mounted along said guide rod. A clamping bolt 27 threaded in this slide 28 serves to lock it in position on the round portion 29. This slide 28 has a protruding pin 28' at the side opposite the slide 18 of the straight edge 5, said pin 28 being adapted to engage a notch (not shown in the drawing) provided in the left side of this slide 18, when the latter is aligned with the slide 28. The image plane I), selected as desired, can be adjusted or fixed by means of said slide 28 determining the position of the straight edge 5. The graduation 7 on this straight edge 5 starts at the right hand side with zero.

The ground plan of the. object or article to be perspectively illustrated is attached to the vertical drawing board 2 in the desired position with respect to the viewers position. As the latters position a fixed point 8 can be always selected and adjusted by a pin insertable in the one or the other of a plurality of holes 8' in a bar 9 extending from the top of the vertical drawing board 2, being slidably mounted therein as indicated by dotted lines at 8", and adapted to completely disappear inside this board, if desired. The drawing board 2 has also a number of holes 8' which are vertically aligned with the holes 8' in the bar 9 and adapted to receive said pin at the place selected for the fixed point 8. A transparent the viewers position.

3 straight edge having in its upper part a plurality of holes 8" adapted to receive the free end of the pin placed in the one or the other of the holes 8 is suspended from the pin to swing like a pendulum about said pin, i. e. about the selected fixed point 8. The holes 8" are interconnected by a slot 19 in such a manner that the straight edge 10 can be longitudinally displaced along the pivoting pin at 8 and adjusted to the desired length at any angular position. As a result of this, points in the far corners of the board 2 can be reached by the straight edge 10. The free or lower end of this straight edge 10 has a handle or knob 11. The center of the transparent straight edge 10 is indicated by a mark line 12 extending throughout the length of this straight edge 10 and intersecting the centers of the holes 8".

A T-square 13 with a graduation 14 is slidable on the horizontal drawing board 1. An edge 15 with a graduation 16 is provided at the left side of this horizontal drawing board 1. This edge 15 is slidably mounted perpendicularly with respect to the T-square 13 and guided by means of grooves (not shown) in a channel provided in and along the horizontal board 1, said grooves being engaged by keys (not shown) on the sides of said edge 15 in the manner known in slide rules. One graduation 16, for example 035, is applied to the edge 15 on its upper side, while another graduation, for example 35-70, is provided on its lower side. The latter graduation can be used by reversely inserting the edge 15 in the channel of the board 1, i. e., with this graduation facing upwardly. The edge 15 can be displaced in its guide channel and extended from the drawing board 1, as indicated in dotted lines at 16', so that the perspective picture III to be drawn can be positioned in the center of the horizontal drawing board 1 when number 35 on the graduation 16 is placed at the selected horizon line, whereby the side 035 of the graduation 16 is used, when the article to be perspectively drawn is above the horizon, while the side 3570 is facing upwardly, when the article is below the horizon. The zero point of this graduation is of importance only for the plotting of the units. The graduations 7, 16 and 14 of the straight edge 5, of the side edge 15 of the board 1 and of the T-square 13, respectively, are made in the same ratio. Consequently, the same number indicated on the graduation 16, for example, 35, corresponds to the horizon as on the graduation 7. The values of the graduation 16 increase with increasing distances from the vertical drawing board 2. The horizontal drawing board 1 is adapted to receive a front or a side elevation of the object or article to be perspectively drawn, and in addition to this a piece of drawing paper on which the per spective illustration is to be drawn.

The apparatus is prepared for making the perspective drawing in the following manner: A ground plan II of the object or article is applied to the vertical drawing board 2 in such a way that the fixed point 8 represents The straight edge 5 set at a predetermined position serves to mark the selected image plane b, which is indicated by the dash-dot line b in Fig. 1. According to the embodiment shown in Fig. 2, the position of the image plane can be fixed and indicated at any desired height by the slide 28 locking the straight edge 5 at such selected position. A geometric view I, for example a side or a front elevation, of the object or article to be perspectively illustrated is applied to the horizontal drawing board 1. The height of the horizon on the vertical drawing board 2 is fixed by means of the perpendicular position of the straight edge 10, the mark line 12 intersecting the graduation 7 of the straight edges, for example, at the number 35. The side elevation I is placed on the horizontal drawing board 1 in such position that all of the points of said elevation above the horizon lie above the horizon line indicated on the board 1, while all of the points below the horizon are located below this indicated horizon line. This horizon line is preferably drawn across the center of the drawing board 1 and 4 the graduation 16 is so displaced or adjusted in and with respect to this board 1 that number 35 lies at the horizon line. This number corresponds to number 35 on the graduation 7, at which place the mark line 12 of the vstraight edge 10 intersects the graduation 7 when said straight edge is in perpendicular position. Thereafter, a piece of drawing paper sufliciently large to receive the perspective drawing III is applied to the horizontal drawing board 1.

The perspective drawing is obtained by the following steps:

Step No. 1

First, the image plane b is determined and fixed. According to Figure 1, the height of a selected point A on the geometric view I is fixed by means of the T-square 13. The corresponding number Ha is read from the graduation 16 on the left side of the horizontal drawing board 1. If the geometric view I is applied to the vertical drawing board 2, the height of the point A will be determined with the aid of the straight edge 5.

Step No. 2

The straight edge 5 is adjusted to that position of the ground plan II where the selected point A is located.

Step N 0. 3

The straight edge 10 is turned about the fixed point 8 by means of the handle knob 11 and brought to a position in which the mark line 12 of this straight edge 10 intersects the number Ha on the graduation 7 of the straight edge 5, which number was obtained or read in Step No. 1.

Step N0. 4

The straight edge 5 is returned to the image plane b and a number Ha is read on the graduation 7 at the intersection of the mark line 12 and the image plane b, i. e. the position of the straight edge 5.

Step N0. 5

The T-square 13 is adjusted to the number Ha, obtained in Step N0. 4, by means of the graduation 16 of the edge 15 on the left side of the horizontal drawing board 1.

Step N0. 6

The mark line 12 of the straight edge 10 is set at that place of the ground plan II on which the selected point A is located. With the straight edge 10 in this position and the straight edge 5 at the height of the image plane b, that number is read on the graduation 7 of this straight edge 5 which is indicated by the intersecting mark line 12 of the straight edge 10.

Step N0. 7

The number obtained in Step No. 6 is read on the gradnation 14 of the T-square 13. A vertical line is drawn through this point. The intersection A of this line with the horizontal line Ha is the point to be located on the perspective drawing III.

In the same way, further points corresponding to one another in the ground plan and elevation are used to locate the corresponding points in the perspective illustration, i. e. the seven steps described in the foregoing have to be applied to obtain each of the points of the perspective drawing. After a number of such, preferably significant, points of the perspective illustration have been determined, these points are connected by lines to complete the picture.

From the foregoing, the construction and operation of the device will be readily understood and further explanation is believed to be unnecessary. However, since numerous modifications and changes will readily occur to those skilled in the art after a consideration of the foregoing specification and accompanying drawing, it is not desired to limit the invention to the exact construc tion shown and described, but all suitable modifications and equivalents may be resorted to, falling within the scope of the appended claims.

I claim:

1. An apparatus for making perspective drawings, comprising two drawing boards, secured to one another and forming an angle therebetween, one of said boards being substantially horizontal and having an area to receive the perspective illustration to be made from an object and another area to which a geometric view of said object may be applied, the other of said boards being substantially vertical and having an area to which at least one other geometric view of said object can be applied at a place to be selected by the viewer with respect to the latters position, a pivot means as fixed point of the viewers position on said substantially vertical board, a straight edge of adjustable efiective length rotatably mounted on said pivot means to freely swing about it and over said substantially vertical board and being adapted to project the height values of said geometric view to the image plane, a horizontal straight edge parallelly guided on and with respect to said substantially vertical board, a graduation on said horizontal straight edge to mark the image plane and read the values of the points of said geometric view, another straight edge parallelly guided on and with respect to said substantially hori- 6 zontal board and an edge with a graduation slidably extensible on and with respect to one of the sides of said substantially horizontal board.

2. An apparatus according to claim 1, wherein said straight edges of said substantially vertical board are transparent and wherein said rotatable straight edge has a center markline extending throughout its length.

3. Apparatus according to claim 1, wherein a bar is slidably mounted substantially in the center and at the top of said substantially vertical drawing board, said bar having at least one hole, wherein said pivot means is a pin placed in said hole with the [pin head extending from said hole and wherein said pivoting straight edge has a plurality of holes each being adapted to be engaged by the pin head to pivotally suspend said straight edge at the selected fulcrum.

References Cited in the file of this patent UNITED STATES PATENTS 1,064,878 Young June 17, 1913 1,346,593 De Clerco July 13, 1920 1,990,040 Launay Feb. 5, 1935 2,210,895 Brownjohn Aug. 13, 1940 2,413,376 Pomeroy Dec. 31, 1946 

